TEETH

Adult
Teeth

An adult has 32 permanent teeth. The
incisors and canine teeth tear and cut food, and premolars and molars are used
to grind and crush. The 4 back teeth are called the wisdom teeth (or third
molars).

Internal
Structure of Teeth

The
3 main parts of a tooth are the crown, neck, and root. The crown (the part of
the tooth you see--above the gums) is covered by a protective, bony layer of
enamel, and the root of the tooth is covered by a sensitive, bonelike substance
called cementum.

A
hard substance known as dentin surrounds the pulp, which contains nerves
(sensing heat, cold, pain, and pressure) and blood vessels (nourishing the
tooth). The gums (or gingiva) fit around the teeth, and the roots of the teeth
fit into sockets in the jawbone. Lining the sockets is a tissue called
periodontium.